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1. Field of the Invention
The invention is related to the field of communication systems, and in particular, to a system that provides data calls using both constant bit rate and variable bit rate connections.
2. Description of the Prior Art
Telecommunication providers use broadband systems to carry data calls. Data calls are calls that are established to carry primarily data instead of voice. One example of a data call is a call originating from a computer through a modem for web surfing. Data calls can carry voice such as through a data call established for video conferencing.
The broadband system must efficiently use the bandwidth for all types of calls to improve overall call performance. One prior solution determines the bandwidth on a call by call basis. FIG. 1 depicts a system level block diagram in an example of a prior solution. The prior solution is disclosed in a pending U.S. patent application Ser. No. 09/304,379, entitled xe2x80x9cSystem and Method for Configuring Bandwidth Transmission Rates for Call Connectionsxe2x80x9d, filed on May 4, 1999, which is hereby incorporated by reference. In FIG. 1, a communication system 100 comprises a call processing system 130 and a call processing system 150. The call processing system 130 and the call processing system 150 are disclosed in a pending United States Patent Application, entitled xe2x80x9cSystem and Method for Processing a Callxe2x80x9d, filed on Nov. 5, 1999, which is hereby incorporated by reference. The call processing system 130 comprises a signaling processor 132 and a routing system 134. The call processing system 150 comprises a signaling processor 152 and a routing system 154. A communication device 110 is connected to the signaling processor 132 and the routing system 134. The signaling processor 132 is connected to the routing system 134 and the signaling processor 152. The signaling processor 152 is connected to the routing system 154 and a communication device 160. The communication device 160 is connected to the routing system 154. The routing system 154 is connected to the routing system 134.
FIG. 2 depicts a message sequence chart that depicts the operation of the communication system 100 depicted in FIG. 1. To initiate a data call, the communication device 110 transmits an Initial Address Message (IAM) in Signaling System #7 (SS7) to the signaling processor 132. The signaling processor 132 processes the IAM and determines the bandwidth for the call based on the IAM. The signaling processor 132 transfers the IAM to the signaling processor 152. The signaling processor 132 generates and transmits a first control message identifying the bandwidth for the call to the routing system 134.
The signaling processor 152 processes and transfers the IAM to the communication device 160. The signaling processor 152 generates and transmits a second control message to the routing system 154 based on the IAM. Subsequent SS7 signaling messages for call setup such as address complete messages are not shown for the sake of clarity. The routing system 134 receives the call from the communication device 110. The routing system 134 processes the first control message and routes the call to the routing system 154 based on the first control message. The routing system 154 processes the second control message and routes the call to the communication device 160 based on the second control message.
The data call is made up of Nxc3x9756K or Nxc3x9764K connections between the communication device 110 and the routing system 134. The Nxc3x9756K or Nxc3x9764K connections are identified by a session identification number. Between the routing system 134 and the routing system 154, the call uses one constant bit rate connection for each Nxc3x9756K or Nxc3x9764K connection for the duration of the call.
Typically, the actual bandwidth needed for the data call varies. One problem is the quality of the call is degraded when the actual bandwidth for the data call is greater than the allocated bandwidth. Another problem is unused allocated bandwidth is not utilized when the actual bandwidth is less than the allocated bandwidth. If the data call is not utilizing the unused allocated bandwidth, then this bandwidth could be utilized by other calls.
Variable bit rate connections have been used for calls between asynchronous transfer mode (ATM) switches. The call uses only as much bandwidth as needed with the remaining bandwidth being allocated to other telecommunication services. Unfortunately, call processing systems do not effectively use both constant bit rate and variable bit rate connections for data calls.
The invention solves the above problems by setting up a constant bit rate and variable bit rate connections as needed for a data call. The invention advantageously uses a constant bit rate connection and a variable bit rate connection to utilize the bandwidth for a data call. Any bandwidth that the data call does not need and use can be utilized for other calls. Thus, the performance of the other calls is improved. Also, the use of a variable bit rate connection ensures handling of the data call when more bandwidth is needed.
A first call processing system receives signaling for the data call. The first call processing system processes the signaling to generate a first instruction to set up a constant bit rate connection for the data call between the first call processing system and a second call processing system. The first call processing system processes the signaling to generate a second instruction to set up a variable bit rate connection between the first call processing system and the second call processing system.
In one embodiment of the invention, the first call processing system generates a third instruction to alter the variable bit rate connection between the first call processing system and the second call processing system based on the capacity needed for the data call. Also, in other embodiments, the first call processing system determines the minimum rate for the constant bit rate connection or the burst characteristics of the data call for the variable bit rate connections.